scholarly journals The Existence of Mating Type Locus and a Possibility of the Sexual Cycle in Koji Mold, Aspergillus oryzae

2014 ◽  
Vol 109 (2) ◽  
pp. 62-69
Author(s):  
Feng Jie JIN ◽  
Katsuhiko KITAMOTO
Keyword(s):  
Aspergillus Oryzae ◽  
Mating Type ◽  
Sexual Cycle ◽  
Type Locus ◽  
Mating Type Locus ◽  
Koji Mold

scholarly journals Fungal Sex and Pathogenesis

2010 ◽  
Vol 23 (1) ◽  
pp. 140-159 ◽  
Author(s):  
Geraldine Butler
Keyword(s):  
Genome Sequencing ◽  
Mating Type ◽  
Fungal Pathogens ◽  
Bloodstream Infections ◽  
Morbidity And Mortality ◽  
Sexual Cycle ◽  
Human Pathogens ◽  
Type Locus ◽  
Mating Type Locus ◽  
Skin Colonization

SUMMARYHuman fungal pathogens are associated with diseases ranging from dandruff and skin colonization to invasive bloodstream infections. The major human pathogens belong to theCandida,Aspergillus, andCryptococcusclades, and infections have high and increasing morbidity and mortality. Many human fungal pathogens were originally assumed to be asexual. However, recent advances in genome sequencing, which revealed that many species have retained the genes required for the sexual machinery, have dramatically influenced our understanding of the biology of these organisms. Predictions of a rare or cryptic sexual cycle have been supported experimentally for some species. Here, I examine the evidence that human pathogens reproduce sexually. The evolution of the mating-type locus in ascomycetes (includingCandidaandAspergillusspecies) and basidiomycetes (MalasseziaandCryptococcus) is discussed. I provide an overview of how sex is suppressed in different species and discuss the potential associations with pathogenesis.

Pneumocystis Mating-Type Locus and Sexual Cycle during Infection

2021 ◽  
Author(s):  
Philippe M. Hauser
Keyword(s):  
Immune System ◽  
Mating Type ◽  
Host Species ◽  
Fungal Infections ◽  
Invasive Fungal Infections ◽  
Sexual Cycle ◽  
Mammalian Host ◽  
Type Locus ◽  
Content Type ◽  
Mating Type Locus

Pneumocystis species colonize mammalian lungs and cause deadly pneumonia if the immune system of the host weakens. Each species presents a specificity for a single mammalian host species. Pneumocystis jirovecii infects humans and provokes pneumonia, which is among the most frequent invasive fungal infections.

scholarly journals Serotype AD Strains of Cryptococcus neoformans Are Diploid or Aneuploid and Are Heterozygous at the Mating-Type Locus

2001 ◽  
Vol 69 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Klaus B. Lengeler ◽  
Gary M. Cox ◽  
Joseph Heitman
Keyword(s):  
Cryptococcus Neoformans ◽  
Mating Type ◽  
Yeast Cells ◽  
Sexual Cycle ◽  
Pcr Analysis ◽  
Environmental Isolates ◽  
Type Locus ◽  
Serotype A ◽  
Mating Type Locus ◽  
Normal Meiosis

ABSTRACT Cryptococcus neoformans is a pathogenic basidiomycete with a defined sexual cycle involving mating between haploid yeast cells with a transient diploid state. C. neoformans occurs in four predominant serotypes (A, B, C, and D), which represent different varieties or species. Rare clinical and environmental isolates with an unusual AD serotype have been reported and suggested to be diploid. We found by fluorescence-activated cell sorter analysis that serotype AD strains are aneuploid or diploid. PCR analysis with primers specific for serotype A or D alleles of theCNA1, CLA4, and GPA1 genes revealed that both alleles are often present in serotype AD strains. PCR analysis with primers specific for genes in the MATa orMATα mating-type loci revealed that serotype AD strains are heterozygous for the mating-type locus. Interestingly, in several serotype AD strains, the MATα locus was derived from the serotype D parent and the MATa locus was inherited from a serotype A parent that has been thought to be extinct. Basidiospores from a self-fertile serotype AD strain bearing the putative serotype AMATa locus showed a very low viability (∼5%), and no fertile serotype A MATa strain could be recovered. Serotype AD strains were virulent in a murine model. Hybrid AD strains could readily be isolated following a laboratory cross between a serotype A strain and a serotype D strain. In summary, serotype AD strains ofC. neoformans are unusual aneuploid or diploid strains that result from matings between serotype A and D strains. Self-fertile isolates fail to undergo normal meiosis because of genetic divergence. Our findings further suggest that serotype A MATa strains may exist in nature.

scholarly journals THE SEARCH FOR MATING-TYPE-LIMITED GENES IN THE HOMOTHALLIC ALGA CHLAMYDOMONAS MONOICA

Genetics ◽  
1986 ◽  
Vol 113 (3) ◽  
pp. 601-619
Author(s):  
Karen P VanWinkle-Swift ◽  
Jang-Hee Hahn
Keyword(s):  
Mating Type ◽  
Resistance Mutation ◽  
Mendelian Inheritance ◽  
Sexual Cycle ◽  
Uniparental Inheritance ◽  
Cell Type ◽  
Erythromycin Resistance ◽  
Type Locus ◽  
Heterothallic Species ◽  
Chlamydomonas Monoica

ABSTRACT The non-Mendelian erythromycin resistance mutation ery-u1 shows bidirectional uniparental inheritance in crosses between homothallic ery-u1 and ery-u1  + strains of Chlamydomonas monoica. This inheritance pattern supports a general model for homothallism invoking intrastrain differentiation into opposite compatible mating types and, further, suggests that non-Mendelian inheritance is under mating-type (mt) control in C. monoica as in heterothallic species. However, the identification of genes expressed or required by one gametic cell type, but not the other, is essential to verify the existence of a regulatory mating-type locus in C. monoica and to understand its role in cell differentiation and sexual development. By screening for a shift from bidirectional to unidirectional transmission of the non-Mendelian ery-u1 marker, a mutant with an apparent mating-type-limited sexual cycle defect was obtained. The responsible mutation, mtl-1, causes a 1000-fold reduction in zygospore germination in populations homozygous for the mutant allele and, approximately, a 50% reduction in germination for heterozygous (mtl-1/mtl-1  +) zygospores. By next screening for strains unable to yield any viable zygospores in a cross to mtl-1, a second putative mating-type-limited mutant, mtl-2, was obtained. The mtl-2 strain, although self-sterile, mates efficiently with mtl-2  + strains and shows a unidirectional uniparental pattern of inheritance for the ery-u1 cytoplasmic marker, similar to that observed for crosses involving mtl-1. Genetic analysis indicates that mtl-1 and mtl-2 define unique unlinked Mendelian loci and that the sexual cycle defects of reduced germination (mtl-1) or self-sterility (mtl-2) cosegregate with the effect on ery-u1 cytoplasmic gene transmission. By analogy to C. reinhardtii, the mtl-1 and mtl-2 phenotypes can be explained if the expression of these gene loci is limited to the mt  + gametic cell type, or if the wild-type alleles at these loci are required for the normal formation and/or functioning of mt  + gametes only.

scholarly journals rme1 Mutation of Saccharomyces cerevisiae: map position and bypass of mating type locus control of sporulation.

1981 ◽  
Vol 1 (10) ◽  
pp. 958-960 ◽  
Author(s):  
J Rine ◽  
G F Sprague ◽  
I Herskowitz
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Type Locus ◽  
Mating Type Locus ◽  
Type Information

Sporulation in Saccharomyces cerevisiae normally occurs only in MATa/MAT alpha diploids. We show that mutations in RME1 bypassed the requirements for both a and alpha mating type information in sporulation and therefore allowed MATa/MATa and MAT alpha/MAT alpha diploids to sporulate. RME1 was located on chromosome VII, between LEU1 and ADE6.

Transformation of protoplasted yeast cells is directly associated with cell fusion

1984 ◽  
Vol 4 (4) ◽  
pp. 771-778
Author(s):  
S Harashima ◽  
A Takagi ◽  
Y Oshima
Keyword(s):  
Cell Fusion ◽  
Mating Type ◽  
Nuclear Fusion ◽  
Yeast Cells ◽  
Nuclear Markers ◽  
Type Locus ◽  
Mating Type Locus ◽  
Yeast Protoplasts ◽  
Yeast Plasmids ◽  
Binominal Distribution

The frequency of cell fusion during transformation of yeast protoplasts with various yeast plasmids with a chromosome replicon (YRp or YCp) or 2 mu DNA (YEp) was estimated by two methods. In one method, a mixture of protoplasts of two haploid strains with identical mating type and complementary auxotrophic nuclear markers with or without cytoplasmic markers was transformed. When the number of various phenotypic classes of transformants for the nuclear markers was analyzed by equations derived from binominal distribution theory, the frequency of nuclear fusion among the transformants was 42 to 100% in transformations with the YRp or YCp plasmids and 28 to 39% with the YEp plasmids. In another method, a haploid bearing the sir mutation, which allows a diploid (or polyploid) homozygous for the MAT (mating type) locus to sporulate by the expression of the silent mating-type loci HML and HMR, was transformed with the plasmids. Sporulation ability was found in 43 to 95% of the transformants with the YRp or YCp plasmids, and 26 to 31% of the YEp transformants. When cytoplasmic mixing was included with the nuclear fusion, 96 to 100% of the transformants were found to be cell fusants. Based upon these observations, we concluded that transformation of yeast protoplasts is directly associated with cell fusion.

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